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Comments 60251 to 60300:

60251. Eric (skeptic) at 22:23 PM on 9 April 2012
       More Carbon Dioxide is not necessarily good for plants.
       R. Gates suggested on the Shakun thread that our current fast rise in CO2 (doubling in about 300 years) could overwhelm the biosphere and therefore cause an overshoot in temperature. That will require several things to be true: first that extra CO2 is a net negative for the biosphere; and/or second that rapid climate changes are also net negative for the biosphere; and third that the biosphere changes will exacerbate the temperature rise causing the overshoot. I would like to discuss some issues with all three of those. Some studies http://www.biosphere.ibimet.cnr.it/File_Publications/thirty%20years%20in%20situ%20forest%20responses.pdf show that elevated CO2 leads to more rapid juvenile tree growth. Other studies http://www.up.ethz.ch/education/biogeochem_cycles/reading_list/koerner_sci_05.pdf show no net change in mature tree growth. The first study also showed that increased CO2 allowed more drought tolerance and the second has neutral results for the 2003 Western Europe drought. For the third item, the biosphere has been modeled for many years to benefit climate models. In this paper http://www.fas.harvard.edu/~eps5/writing_assignment/T_GHG_RECON/bonan_2008_forests.pdf they summarize some basic results: reduced albedo (causing net warming) versus increased transpiration (causing net cooling). I don't see any resolution yet to the question of net climate result. The bottom line is that R. Gates concern is somewhat speculative. The climate may overshoot due, essentially, to desertification. It may undershoot due to enhanced net biosphere growth if the desertification is essentially localized (which I believe it is) and the "warmer = wetter" is the net result for the world (that discussion belongs on a different thread).
60252. CBDunkerson at 22:07 PM on 9 April 2012
       2012 SkS Weekly Digest #14
       "How optimistic are you that the human race will get its act together in time to stave off catastrophic climate change?" Depends on how we are defining "catastrophic". That could range anywhere from an increased incidence of natural disasters (which we have already seen and thus cannot possibly stave off) to a mass extinction or sudden sharp decline in human population. Many other activities of humans are also contributing to mass extinction and it thus isn't clear whether we'll be able to avoid that even if we get climate change under control. Ditto human population. It now seems clear that solar power technology will drop well below fossil fuel costs (even ignoring the imbalance in externalities and subsidies) over the next few decades. However, a switchover to solar power would also require improvements to power distribution (which will require political will) or storage (which will require technological breakthroughs). I see very little evidence of political will. Thus, to me it all comes down to 'batteries'. If we develop ways to store energy roughly four times as quickly and compactly in the next decade or so then there will be a 'sea change' away from fossil fuel power to solar. If not we'll continue on as we have been for another thirty years or more and things will eventually get very bad indeed. Obviously Bern's 'global CO2 scrubbers' or some other technological breakthrough could also change the game, but solar and batteries are the current front-runners in my mind.
60253. CBDunkerson at 21:38 PM on 9 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       "According to the Shakun et al. data, approximately 7% of the overall glacial-interglacial global temperature increase occurred before the CO2 rise, whereas 93% of the global warming followed the CO2 increase." How exactly is this derived, given that neither the temperature increase nor the CO2 increase was a singular event? In previous examinations of this question an important point has been that the (then supposed) initial increase in temperatures caused an increase in CO2 levels... which caused a further increase in temperatures... more CO2... et cetera. The changes were going on concurrently, with only the initial triggers being offset. That argument made sense and still does... but then how do you compute '93% after' from two concurrent processes? My best guess is that they are looking at the time period between the start of the orbital forcing and the start of the CO2 increases and finding that it accounted for 7% of the total temperature rise. However, that might then create a perception that the 93% 'after the CO2 increase' was entirely due to the CO2, when in reality the continued orbital forcing was also likely involved. That said, a lot of the reporting on this has described it as a change from 'CO2 lagged temperature' to 'temperature lagged CO2'. However, the actual study still finds that the warming from the orbital forcing came first... so the increase in atmospheric CO2 levels still started after the increase in temperatures. That temperature increase was just concentrated first in the Northern hemisphere (as expected due to the forcing) and then in the Southern (the real 'new' finding of the study) apparently due to AMOC. Using the 'accelerated' Southern hemisphere temperature as a global value made the CO2 lag look longer than it was, but even with the 'global' values used by this paper they found 7% of the warming prior to the CO2 increase. The 'skeptics' who aren't thus appear to be freaking out over how the paper has been reported without stopping (or possibly being able) to understand what it actually says.
60254. Lionel A at 21:35 PM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       keith @13 & dana1981 @15 On the origins of CAGW Wiki gives a brief resume of one potential trigger for this term here, John T. Houghton, see under Falsely attributed . Tim Lambert had a post on this at Deltoid, Akermangate: Piers Akerman fabricates some more .
60255. Sapient Fridge at 21:04 PM on 9 April 2012
       2012 SkS Weekly Digest #14
       Bern wrote: "someone might invent a solar-powered gizmo that sucks CO2 from the atmosphere, converts it into solid carbon + O2, and just keeps powering on." Aren't such machines called "plants"?
60256. Bern at 20:26 PM on 9 April 2012
       2012 SkS Weekly Digest #14
       How optimistic are you that the human race will get its act together in time to stave off catastrophic climate change? Not at all. I think there will be catastrophic impacts, and that it will be these catastrophic impacts that finally trigger global action to stop CO2 emissions. I also think some of these might occur much sooner than later. But, as always, it's a question of degree. With sufficient resources thrown at the problem, atmospheric CO2 could be sequestered technologically at a similar rate to emissions, so we might get 'back to normal' within only a century or so after tackling the problem. On the other hand, so many resources are going to be taken up with mitigation and adaptation to the early impacts, that, combined with the economic impacts of those climate impacts, there might not be enough spare to work on techno-sequestration. On the gripping hand - someone might invent a solar-powered gizmo that sucks CO2 from the atmosphere, converts it into solid carbon + O2, and just keeps powering on. In which case, we've at least got a running chance...
60257. John Russell at 18:43 PM on 9 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       @question #4 Here's the simple explanation. The ultimate driver of temperatures on our planet is energy from the sun, which is affected by the variations in the shape and offset of the Earth's orbit and wobbles of our axis. Changes in these, immediately preceding the end of the ice ages, triggered the rise in temperature which led to a release in CO2 and the warming that took place (as described in the post). So to answer the question: Earth's energy balance always seeks equilibrium which, once the variations in orbit and wobble had then stabilised (or more correctly 'neutralised' each other), our planet eventually achieved. Further warming then stopped and we settled down to a new, warmer, state which -- this time round -- happened to coincide with a level of human development conducive to the beginnings of civilisation. As I started by saying this is a very simplistic explanation. I'm sure the scientists here will be happy to provide more detail (or, for that matter, correct me if I've oversimplified anything).
60258. question at 17:44 PM on 9 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Can anyone clarify the reasons for the levelling off of both CO2 and temperature at the end of the transition? Thanks.
60259. Sapient Fridge at 17:16 PM on 9 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Good article, but some typos: "feebacks", "mananges", "equilibirum", "unerstanding" and "depocted" (Delete after fixing if you want)
60260. R. Gates at 15:23 PM on 9 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       Excellent summary of the Shakun et. al. paper and the predictable skeptic response by Easterbrook et. al. In terms of sensitivity, I personally think the 3C estimate is pretty solid, as the rate of CO2 growth, not just the actual raw number must be considered. The response of the climate to a doubling of CO2 that takes 10,000 years versus 350 years is a different dynamic. Specifically, natural negative feedback pathways become overwhelmed when the doubling occurs in the shorter time frame. Not only can short-term feedbacks be overwhelmed, long-term biosphere feebacks might as well. Additionally, in the case of the current Anthropocene, it is not just CO2 that is increasing from human activity, but N2O and methane as well. Thus, even if the sensitivity of the climate to a doubling of CO2 from 280 ppm to 560 ppm that took 10,000 years is around 2.5C, it may not be the case that this is the same sensitivity for a doubling that takes 350 years. What might happen, for example, is a classic overshoot situation where, even if we manage to keep CO2 at 560 ppm, because of the rapid rise of CO2, and the overwhelming of the feedback processes. the system overshoots what would have been an equilibrium temperature of 2.5C, and spikes higher. In spiking higher, some new biosphere, hydrosphere, or cryosphere threshold is crossed, that mananges to send the system to a higher equilibirum temperature because the character of the system has been changed by the rapidity of the CO2 spike.
60261. geologic at 15:15 PM on 9 April 2012
       Shakun et al. Clarify the CO2-Temperature Lag
       good summary...can anyone add detail to how the see-saw works? All I've been able to find is somewhat vague descriptions that heat accumulates in the tropics when the AMOC shuts off, this heat then somehow gets transferred to the southern ocean....how? what turns on the S. Atlantic circulation system that re-distributes the heat southward out of the tropics?
60262. Tom Curtis at 15:08 PM on 9 April 2012
       New Understanding of Past Global Warming Events
       danielc @1, currently the rock weathering process is approximately in balance with global CO2 emissions from volcanoes. We know this because of the very nearly stable CO2 concentrations over the holocene. That means that the rock weathering process removes approximately 0.224 to 1.1% of annual anthropogenic CO2 emissions every year. Put differently, for each year of emissions at current rates it will take between 90 and 450 years to remove the emitted CO2 from the atmosphere. At least it would if there were no ongoing CO2 emissions from volcanoes. Put another way, if the rate of CO2 removal by rock weathering where doubled while the rate of CO2 emissions from volcanoes remained the same and humans stopped all CO2 emissions, it would take on average 5500 year to remove the emissions of the last 20 years from the surface reservoirs of CO2 (ocean, soil, biosphere and atmosphere). Fortunately increased warmth does increase the rate of rock weathering by increasing chemical reaction rates directly, and by increasing the strength of the water cycle, thus increasing the rate of erosion. But it may still be from tens to hundreds of thousands of years before CO2 levels are restored to pre-industrial levels.
60263. Tom Curtis at 14:45 PM on 9 April 2012
       2012 SkS Weekly Digest #14
       Caerbannog @1, I, for one, find your results very interesting if not entirely unexpected. Indeed, I think the work that you and other amateur climate scientists have done of the surface record should be given much more prominence. To that end I suggest that you contact John Cook so that your results can be published as a blog post here on SkS, rather than simply being lost in the comments. With regard to the actual results, I noticed that some stations in the sparse network are very close together. There appear to be two from Alaska, for example. There are also two from northern Scandinavia, and one each from east Texas and Louisiana (I think). These stations might be seized on as distorting the result, although I strongly suspect they do not. Perhaps you could modify your program to select boundary locations to maximize the average distance between stations (or perhaps to maximize the cube root of the distances between proximal stations to give greater weight to avoiding close pairings) so as to avoid this criticism. Alternatively you could just drop out the shortest of any two records from the analysis where they are closer than some minimal distance. (I am sure you can think of other ways to avoid the issue as well.) Further, as an antipodean, I would appreciate maps of station sites that show the entire globe, and not just the North Atlantic and surrounding lands.
60264. Daniel Livingston at 14:39 PM on 9 April 2012
       2012 SkS Weekly Digest #14
       How optimistic are you that the human race will get its act together in time to stave off catastrophic climate change? This is quite a subjective question, so forgive me for an answer that may appear quite subjective on a scientific site such as SkS. I am actually optimistic about the future, but not about humanity fixing this climate issue. Extraordinary problems require extraordinary solutions, so I am not looking to science, technology, markets, policies or regulations to fix this. According to my belief in the Bible, outside intervention will arrive before humanity succeeds in destroying the planet and ourselves. My optimism, however, is not placed in some inherent capacity of nature to always come up trumps against the onslaught of human activities, or in human ingenuity to always result in progress and improvement. The Bible paints a different picture. According to the Bible humanity can succeed and achieve improved life, but only a minority of humanity will find such success.
60265. Chris G at 14:11 PM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       In 2005, Lindzen wrote: "... Let me summarize the main points thus far: 1. It is NOT the level of CO2 that is important, but rather the impact of man made greenhouse gases on climate. 2. Although we are far from the benchmark of doubled CO2, climate forcing is already about 3/4 of what we expect from such a doubling. 3. Even if we attribute all warming over the past century to man made greenhouse gases (which we have no basis for doing), the observed warming is only about 1/3-1/6 of what models project. We are logically led to two possibilities: 1. Our models are greatly overestimating the sensitivity of climate to man made greenhouse gases, or 2. The models are correct, but there is some unknown process that has cancelled most of the warming. ..." I'm thinking he egregiously overlooked a 3rd possibility, that the system has not yet reached an equilibrium.
60266. caerbannog at 13:29 PM on 9 April 2012
       2012 SkS Weekly Digest #14
       (This is a modified version of a post I put up in the realclimate.org "unforced variations" thread). Off and on, I had been experimenting with some "simple minded" processing methods applied to the GHCN raw temperature station data. I have found it surprisingly easy to replicate the published NASA/GISS "meteorological stations" index with some pretty simple data-crunching procedures applied to *raw* station data. The global temperature record is really amazingly robust -- the global-warming signal just "jumps out of the data" even with the crudest processing approaches. I’ve been trying to put together a simple, easy to understand visual demonstration of the reliability/robustness of the global temperature record, in an easy-to-digest “eye candy” format -- i.e. something that won’t make non-technical folks’ eyes glaze over. The goal is to have an easy to comprehend "visual refutation" of the most popular "skeptical" claims about the global temperature record. With that in mind, I put together 3 images. 1) A plot of what I call the “Sparse Rural Stations Index", which is just a set of global-average temperatures computed from a very small number of scattered rural stations, displayed along with the official NASA/GISS “Meteorological Stations” temperature index. The procedure used to generate the "Sparse Stations Index" is really quite simple: Divide up the globe into 20 degrees x 20 degrees grid-elements (at the Equator; longitude dimensions adjusted as you go N/S to keep grid-element areas approximately constant). Search each grid-element for the rural station with the longest temperature record. Use one and only one station for each grid element. About 85 stations were selected via this procedure. Because of varying station record lengths, data-gaps, etc., significantly fewer stations reported data for any given month/year. Over the 1880-2011 time-period, an average of about 50 of the selected stations reported data for any given month/year. Compute the year/month temperature anomalies (relative to the standard NASA 1951-1980 baseline) for the selected stations, and just straight average the anomalies all together for each year. 2) A Google-Earth visualization of stations used to compute the NASA/GISS “Meteorological Stations” index. (If you have a bit of programming experience, getting the station lat/long metadata into Google-Earth readable format is pretty easy.) 3) A Google Earth visualization of stations used to compute the “Sparse Rural Stations Index”. The results pretty convincingly demonstrate the following: 1) UHI is a non-issue (I used only rural stations). 2) Data "homogenization" is a complete non-issue (I used only raw temperature data). 3) The global temperature record is incredibly redundant and robust -- you can really throw away ~98 percent of the temperature stations and *still* confirm the NASA/GISS global temperature estimates.
60267. Chris G at 13:04 PM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Eric, Also, Lindzen's conclusion from the empirical results assumes that the oceans, ice sheets, permafrost, methane clathrates, and ecologic zones are already in an equilibrium state with the current radiative imbalance. That seems pretty absurd to me. I'm not saying that the current measurements are wrong; I am saying his conclusion based on them can only be correct if the all the above conditions are met, and I think it is pretty clear that they are not.
60268. Chris G at 12:42 PM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Note: On a long average, energy in is equal to energy out; when I said balance point, I meant the equilibrium temperature at which SW absorbed and LW emitted are equal.
60269. Chris G at 12:37 PM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Eric (#17), I may have made an inference that Lindzen has not explicitly stated, but for instance, here is an explanation of his for how heat fluxes between equator and pole can make it so that summers are to warm for snow and winters are too cold (loosely paraphrased). The article talks a lot about snow and ice, and Hadley cell circulation. A note on orbital control of equator-pole heat fluxes Since the phase of water on the surface does not add or subtract energy from the earth system, and neither do convective currents, I infer that he is talking about albedo changes. As I understand it, the vast majority of the energy coming and going from the earth does so through radiative processes. He does state that changes in flux can change the global temperature (which is a function of energy content), and for that to be the case to the extent that was observed in the glacial-interglacial cycles, there has to be a change in the balance point between radiative energy in, and radiative energy out. Changing albedo is the only way that is apparent to me for the presence or absence of ice and snow to have that effect. I did not see any mention of water vapor feedback in that paper; so, I do not think he was thinking of that being a GHG forcing or feedback. That paper is 20 years old; so, he may have changed his mind (or modified his hypothesis), but I was not able to quickly find anything more recent where he described a mechanism by which glacial cycles should coincide with Milankovitch cycles, and not have GHGs play a significant role. There as another aspect. Energy lost is proportional to the fourth power of the absolute temperature (Stefan-Boltzmann). I suspect that means that a body that has a more equal distribution of temperature looses less energy than a body where the energy is concentrated more in some region. (Imagine a plate with one half several degrees higher than the other half versus a plate with the same heat content uniformly distributed.) So, how the energy is distributed would affect the overall balance point (global temperature). However, he talks about how the winter heat flux between pole and equator is increased during periods of high asymmetry, and I think that means that there is more energy distribution taking place. More energy distribution should lead to less total energy loss. This aspect does not agree with his conclusion; so, I do not think this is what he had in mind for how changes in tilt account for the glacial cycles. Still thinking that he was implying albedo changes.
60270. dana1981 at 12:17 PM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       I agree that for the most part Lindzen has been pretty consistent - and consistently wrong, of course. Personally I prefer it when people are able to admit they're wrong, as opposed to steadfastly repeating the same arguments after they've been proven wrong.
60271. danielc at 11:47 AM on 9 April 2012
       New Understanding of Past Global Warming Events
       I think those land bridges were tectonic in origin, rather than sea-level related... 1) continental collision, subduction and plate motion brought new territories into reasonable proximity, and in some cases my have opened sub-aerial connections.. 2) Loss of ice in the Arctic, coupled with still connected Norway/Spitzbergen/Greenland/Canada (in short, North Atlantic rifting was nowhere near complete, and Labrador Sea was no nearly open...) gave rise to passable pathways from Asia, through N. Europe, to N. America.... that's the basic idea here (http://www.pnas.org/content/103/30/11223.full ). One aspect of the PETM that is not discussed here is the impact of North Atlantic Volcanic Province activity - massive shallow submarine flood basalt eruption.... there are those who point to that as the trigger for a lot of the early Eocene craziness.
60272. actually thoughtful at 11:20 AM on 9 April 2012
       New Understanding of Past Global Warming Events
       Curious why a land bridge appeared during warming - wouldn't that indicate higher sea level, and therefor fewer land bridges?
60273. danielc at 10:51 AM on 9 April 2012
       New Understanding of Past Global Warming Events
       Feedbacks, feedbacks everywhere you look. I'm still struggling with some of the rates, however: the temperature/CO2 feedback works pretty fast, and the cloud/H2O vapor feedback works in concert and at similar rates. One question about this I have is this: Where is the silicate weathering (carbon sequestration) signal in all this? Is it: warming reduces ice and increases available rock for weathering, but that is a much slower process? Or is it: warming reduces ice, increases available rock, but only until sea level rise covers more rock than is exposed by ice loss? Or is it: absent mountain building on a globally significant scale, warming/CO2 release/water vapor increase effects will swamp the silicate weathering signal over long periods of geological time?
60274. Eric (skeptic) at 10:43 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       The claim of shifting goal posts is correct in some cases, but it is better to argue against the argument than an alleged change in argument. Lindzen has made a consistent argument against high sensitivity for at least a dozen years: http://www.pnas.org/content/94/16/8335.full. I have always made the argument that models will not calculate water vapor feedback without properly modeling weather: http://www.realclimate.org/index.php/archives/2006/08/the-missing-repertoire/comment-page-1/#comment-17399 and here
60275. Eric (skeptic) at 09:46 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Chris G, the Lindzen's London Illusions thread doesn't present any comments by Lindzen about albedo. It looks like only the response to Lindzen references albedo, specifically the claim that Lindzen is not accounting for cooling by aerosols. It looks like the argument by Lindzen is simply empirical, that there was not enough warming created by the present CO2 concentration to justify the 3C sensitivity claim.
60276. John Russell at 08:46 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       @Dana #15 I think you are very right with regard to the shifting of goalposts and I've already detected it in many quarters. A significant number of fake sceptics are now saying, "of course it's warming and human caused" (and pretending they've always believed that) but then going on to say that their complaint is just with the 'alarmists' who suggest the outcome might be catastrophic. And of course they do nothing to bring up to speed those in denial who are still back at the 'it's all a hoax' stage.
60277. dana1981 at 07:07 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       John Russell @9 - we'll be publishing a post on the Shakun et al. paper you link later tonight. keith @13 - I view "CAGW" as the next step for climate denialists who are finally willing to admit the planet is warming and humans are somewhat to blame. The next phase of denial is "sensitivity is low and therefore it won't be bad", and thus they construct this "CAGW" strawman, claiming that anyone who acknowledges that the consequences will indeed be bad is a "CAGW alarmist". It's a goalpost shift.
60278. dana1981 at 07:00 AM on 9 April 2012
       CO2 lags temperature
       I just updated this rebuttal with some information (and 1 figure) from Shakun et al. (2012) which gives more information and nuance regarding the CO2-temperature interaction. We'll publish a post on the paper tonight.
60279. Chris G at 06:51 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Eric #7. IIRC, Lindzen focuses on albedo changes being more influential than GHC changes, but others have calculated that albedo changes were not nearly enough by themselves. In any case, we are seeing significant albedo changes as a result of GHC induced warming. So from a practical standpoint, positive feedbacks may make it so actual nature of the initial forcing matter little.
60280. keithpickering at 06:16 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Taking a cue from the Carbon Brief thread, isn't the term "CAGW" essentially a strawman rather than an actual scientific theory? Has anyone other than a climate skeptic actually used this as a term of art? It gets zero hits on Google Scholar.
60281. keithpickering at 06:13 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Biosphere response over the long-term must be a positive feedback, at at least in terms of albedo: as climate zones move poleward, they all shrink in area (due to latitude change) except for the equatorial rainforest zone. The shrinking zones include the bright polar zone and the bright subtropical desert zone, while the expanding rainforest is dark.
60282. threadShredder at 04:37 AM on 9 April 2012
       Fred Singer Debunks and then Denies
       @Dikran Marsupial: I was wondering if anybody had taken a look at the comments of Singer's AT science-rewrite. The comments are truly something to behold in that people with absolutely no science background are so rock-solid cocksure of their convictions against scientists. (Here in the U.S., that goes also for certainly against learned authority in economics, health care, etc.) Thanks again for responding here and attempting to respond to Singer at AT. As for me, I'm continuing on through all the myth rebuttals here and trying to keep up with the posts as they come. Keep up the good work.
60283. Dikran Marsupial at 04:18 AM on 9 April 2012
       Fred Singer Debunks and then Denies
       @threadshredder, I have noticed over the years of discussing a variety of topics on USENET and the WWW that quite often delusions of this nature are often paradoxically strengthened by them being proven wrong. The one with the delusion is unable to accept the criticism and finds ways to dismiss it on any basis they can, rather than face the fact that they are wrong and are making a fool of themselves. Instead they percieve themselves as having won the argument, thus reinforcing the delusion. As it happens, I tried posting a reply to Prof. Singers latest nonsense in American Thinker, but it doesn't appear to have made it past the moderator. This is what I wrote: It is ironic that Prof. Singer accuses Mann of dishonesty when his use of the IPCC 1990 diagram as evidence of the MWP is deeply misleading. It is a schematic diagram (not data) of central england temperatures (not global) and the last point of the graph shows temperatures representative of the first half of the 20th century (so it doesn't show any of the warming that has ocurred since 1950 or so. See the appendix of this paper http://pubs.giss.nasa.gov/docs/2009/2009_Jones_etal_2.pdf which discusses the origin of this diagram, and updates it using CET measurements up to 2007 (Figure 7), which shows that "recent measured warming may be comparable with presumed earlier warmth" (actually they are higher according to the graph, but Jones et al in usual scientific style avoid overstating the results). Prof Singer also fails to mention Wahl and Amman (2007) addressed the criticism of Mann's method and that other proxy analysis, constructed using other methods, produce essentially the same result, so why doesn't Prof. Singer criticise them as well?
60284. Joel_Huberman at 04:16 AM on 9 April 2012
       Eocene Park: our experiment to recreate the atmosphere of an ancient hothouse climate
       Many thanks to Andy S for a fascinating article. In follow-up to John Russell's comment @#11, the man who is "ahead of us", S. Matthew Liao of New York University, suggests several ways (mostly foolish, in my opinion) in which human beings might be "engineered" to diminish their impact on the climate and/or to diminish the impact of the climate on them. So far as I could tell when I skimmed through his paper on the subject, he did not suggest any method by which human beings could be made more heat-tolerant. Therefore the concerns raised by John Russell @#3, Bernard J @#8, and Riccardo @#10 still stand.
60285. threadShredder at 03:59 AM on 9 April 2012
       Fred Singer Debunks and then Denies
       @Dikran Marsupial: Thanks for your reply and I understand completely. (Americans are, on many important topics, subjected to the right's nonsense day after day after... and are having a hard time with all of it.) But Singer has been refuted repeatedly on every topic for which he has taken up arms against the rest of the scientific community. There comes a time when Hanlon's razor becomes so dull from overuse that you just have to assume what explains Singer's constant going-against-the-grain is the unfortunate obvious. Nevermind what I think of Singer, and I do think of him as I've already indicated. In the end, that is unimportant. What I hope is that *every* time he takes to any microphone afforded him, he is responded to and shouted down with the scientific evidence. It is my guess that, at this point, these types of characters understand only one thing, and isn't going to be based on facts and reason, but their own self-analysis of their worth. That must take a hit.
60286. Dikran Marsupial at 03:54 AM on 9 April 2012
       CO2 lags temperature
       Eric, yes in the circumstances shown in figure 1 CO2 is acting as a feedback to Milankovic forcing, so it is unsurprising that CO2 lags temperature. So what? That doesn't mean that the current rise in CO2 is natural rather than anthropogenic (it is very straightforward to disprove that hypothesis). Also we don't have one hemisphere of CO2, CO2 is well mixed in the atmosphere, and it only takes a year or so for fossil fuel CO2 generated in the northern hemisphere to reach the southern hemisphere.
60287. John Mason at 03:49 AM on 9 April 2012
       Submerged Forests off the coast of Wales: a Climate Change Snapshot
       Orcman, you are quite right, although the definition-as-accepted leaves some room for query - think of Sarn Helen, the Roman route up through Mid-Wales. When I crewed on the sea-angling boats out of Aberystwyth donkeys years ago the Sarn Cynfelyn reef, home of the black bream, was always called the Causeway by the local boys. There's a mark about 6 miles out along that reef that we all call The Wall, and when you go over it slowly on a boat with the sounder running you can immediately see why. Wants diving, one clear day. Almost certainly natural, but would be a good one to clear up! Cheers - John
60288. Eric (skeptic) at 03:35 AM on 9 April 2012
       CO2 lags temperature
       Dikran, I agree it can be both. But there's not much uncertainty in FIgure 1 above; temperature leads and CO2 is a feedback because the best theory for cycles is tilt and eccentricity driving temperature (unless tilt and eccentricity drives CO2). I don't have a copy of the recent paper so I can't evaluate the claim that a hemisphere of CO2 drives two hemispheres of warming, but it doesn't make much sense to me.
60289. R. Gates at 03:23 AM on 9 April 2012
       Climate Scientists take on Richard Lindzen
       Eric @ #8, I don't think the biosphere response to the kinds of increases in CO2 that we've seen over the past few hundred years are known in great detail yet. Species migration and habitat changes may create a variety of effects that may be positive or negative feedbacks to the initial warming caused by CO2 increases. Ocean acidification is another potential biosphere related response. My point is that supposed "experts" in climate sensitivity, such as Monckton presents himself as cannot possibly known what the long-term climate sensitivity to any given increase in CO2 will be as they are so complex and varied. We've not yet seen the complete equilibrium response to 392 ppm of CO2, so how can anyone possibly know with the kind of certainty that Monckton parades around with what the 560 ppm will be? Probably the best line of research into coming close to estimating what the long-term response will be is looking at the climate of the mid-Pliocene or even Miocene periods, and in doing so, 3C seems quite a reasonable estimate for a doubling, if not a bit low.
60290. Dikran Marsupial at 03:21 AM on 9 April 2012
       Fred Singer Debunks and then Denies
       @threadshredder, Richard Feynman said "The first principle [of science] is that you must not fool yourself, and you are the easiest person to fool.". Sadly the human ability for self deception appears to be almost unlimited, and self-deception on a history of topics may simply be due to Prof. Singer's susceptibility, rather than deliberate dishonesty. There are a number of good reasons to opt for this interpretation: Firstly Hanlon's razor ("never attribute malice to that which can be adequately explained by thoughtlessness") and its variants is a good maxim for life, on the grounds that we should hope others adopt it when we are thoughtless, stupid or self-deluded. Secondly, it can lead us to disregard arguments as deception and not be open-minded. Thirdly, what really matters is the science and the science is strongly on our side; the "skeptics" know this and so insead try to focuss on rhetoric and making the discussion personal, so accusations of dishonesty are what they want you to do; stick to the science if you want to make them uncomfortable. Lastly it is against the comments policy at SkS! I understand where you are coming from, but fairness, open-mindedness and scientific accuracy are the best reply to this sort of thing. In otherwords, never wrestle with a pig - you'll both get dirty, but the pig will enjoy that! ;o)
60291. threadShredder at 02:31 AM on 9 April 2012
       Fred Singer Debunks and then Denies
       @DSL and Dikran Marsupial: Thanks for your replies. I'm very new to climate science but have learned a lot from this site, and would like to take this opportunity to thank all the contributors for their excellent work and, obviously, the significant amount of time that is required to do that work. I'm at the point that I can, by spending a lot of time, refute someone like Singer and his nonsense, but it's not easy for me. One of the problems as I see it is that these deniers and faux skeptics have not been given the proper level of public scrutiny and scorn from people who know the issues expertly. It's to the point that it almost requires bringing back public stocks. I'm American so I am painfully, painfully aware of the war on science and reason that is going on by one side of the political "debate." The Republicans have decided that it would be a good thing to take the country back to a time before the Enlightenment. I believe that they must be stopped and so it it my opinion that whenever one of the would-be country's pre-Enlightenment wishers takes to the podium, they must be confronted. That's why I hope everytime Singer and those like him get a forum to speak, that they are confronted with their errors. Dikran Marsupial: Unlike you, I find it [accusation of dishonesty snipped] Hopefully these people can be stopped and the "average" citizen, here in the U.S. and everywhere else, understands what an assault on evidence and reason and the world's future they are waging.
       Moderator Response: TC: As noted by Dikran Marsupial, accusations of dishonesty against anyone are against the comments policy. Please consider carefully whether it is really worthwhile having your post snipped or simply deleted before making such accusations on this site in future.
60292. KR at 00:54 AM on 9 April 2012
       A detailed look at climate sensitivity
       Eric (skeptic) - Scafetta's work really isn't about climate sensitivity, but about causality; he attributes mid-term climate change to solar/planetary cycles with ill-defined relationships, dismissing the influence of GHG changes and other forcings. The proper threads for discussing Scafetta and West would be Scafetta's Widget Problems or Loehle and Scafetta find a 60 year cycle causing global warming, rather than dragging this thread off-topic.
60293. Dikran Marsupial at 00:19 AM on 9 April 2012
       CO2 lags temperature
       Eric (skeptic) that is a false dilemma, CO2 can lag temperature, or it can lead temperature, and there is evidence for both in paleoclimate data. Generally it depends whether CO2 is acting as a feedback (mostly due to the dependence of the ocean/atmopshere carbon exchange on temperature) or a forcing (e.g. rapid chemical weathering following the uplift of the Appalacians reducing atmospheric CO2 leading to cooler temperatures). Another example of CO2 acting as a forcing is the increase in atmospheric CO2 from burning fossil fuels leading to increasing temperatures.
60294. Eric (skeptic) at 00:15 AM on 9 April 2012
       A detailed look at climate sensitivity
       scaddenp, I have owed you a discussion of sensitivity for quite a while now. Here's a link to Scafetta and West 2006 containing estimates of climate sensitivity to solar energy increases. Scafetta in particular has been critiqued here on several threads for proposing terrestrial climate cycles based on solar system cycles which don't appear to be supported. Also critiqued for ascribing too much of the recent warming to a more active sun (both increased TSI and other less well-defined effects like GCR changes). If Scafetta is wrong about the contribution of solar changes to recent warming (i.e. he overestimated the contribution) then his low estimates of climate sensitivity to solar changes in the paper linked above should be even lower. I am assuming that climate sensitivity to solar secular changes (i.e. 100 years or so, not the solar cycle) is the same as climate sensitivity to CO2 forcing changes. If I am wrong, please correct that. If not, then a climate sensitivity of, on the low end, 0.2K per W per m2 leads to a 0.74 C per CO2 doubling. On the high end in that paper, 0.57K/W/m2 leads to 2.1C for a doubling of CO2. Wikipedia says 0.7K/W/m2 for solar and rounds up 3.7 to 4.0 to arrive at 2.8C which they round up to 3C.
60295. Eric (skeptic) at 23:21 PM on 8 April 2012
       CO2 lags temperature
       John Russell I think we are going to need more research to decide whether CO2 lags temperature or vice versa. The simple model in my mind is that temperature increases are amplified by CO2 increases. This is due to slow feedbacks on the order of hundreds to a 1000 or so years, things like CO2 from permafrost and methane from the deep ocean. The leading or lagging of CO2 could be more complex however since the systems are very nonlinear. For example some initial warming could cause a pulse of CO2 that leads to a larger warming. That may be what was being observed in the paper you linked to.
60296. Bernard J. at 23:01 PM on 8 April 2012
       Climate Scientists take on Richard Lindzen
       Phil at #6. I suspect that in the case of anthropogenic global warming, Planck's quote could be paraphrased thus:

       An established but ideologically-unpalatable scientific truth does not triumph by convincing its opponents and making them see the light, but rather its its truth eventually manifests regardless of any human disbelief, and a new generation grows up that is familiar with the truth - and despising the previous generations that were too blinkered to acknowledge the scientific truth and address it in time.

60297. John Russell at 22:44 PM on 8 April 2012
       Climate Scientists take on Richard Lindzen
       @Eric #7 I think you're going off topic; but I think you'll find what you need here: 'Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation'. There's a BBC report on the paper here.
60298. Eric (skeptic) at 22:02 PM on 8 April 2012
       Climate Scientists take on Richard Lindzen
       R. Gates, what evidence points to biosphere lag? If there is a lag, wouldn't there eventually be more CO2 uptake and more transpiration?
60299. Eric (skeptic) at 21:59 PM on 8 April 2012
       Climate Scientists take on Richard Lindzen
       "There is an interesting dichotomy in [Lindzen]'s line of argument between the implication in the rest of the presentation that the climate is rather insensitive to change, and the observation that, on glacial interglacial scales, even very small changes in energy input led to massive change." Oversimplified, ignores the differences in feedbacks, see here. The more significant glacial/interglacial changes were not in energy, but in tilt and eccentricity leading to seasonal albedo and weather pattern changes leading to global average temperature changes. The worst case at present is if the CO2 increases lead to less concentrated convection, less meridional flow, less storminess on average, stronger polar jets (more positive AO), etc. That could certainly happen and I cannot credibly dispute models suggesting that. But others have suggested the opposite.
60300. Phil at 21:10 PM on 8 April 2012
       Climate Scientists take on Richard Lindzen
       Apologies if this is deemed off-topic, however I recently chanced upon this somewhat depressing quotation by Max Planck:

       A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather its opponents eventually die, and a new generation grows up that is familiar with it.

       Source here. - it would be interesting to know the context of his remarks, although I would guess he was thinking of quantum physics. Now AGW may not be a particularly new scientific truth, but the quotation does emphasize the difficult of overturning beliefs or assumptions that may have fueled a distinguished career, even amongst scientists. Do we really have to wait until Lindzen, Spencer et al to pass away ?

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